First molecular phylogenetic insights into the evolution of Eriocaulon (Eriocaulaceae, Poales).

Eriocaulon is a genus of c. 470 aquatic and wetland species of the monocot plant family Eriocaulaceae. It is widely distributed in Africa, Asia and America, with centres of species richness in the tropics. Most species of Eriocaulon grow in wetlands although some inhabit shallow rivers and streams with an apparent adaptive morphology of elongated submerged stems. In a previous molecular phylogenetic hypothesis, Eriocaulon was recovered as sister of the African endemic genus Mesanthemum. Several regional infrageneric classifications have been proposed for Eriocaulon. This study aims to critically assess the existing infrageneric classifications through phylogenetic reconstruction of infrageneric relationships, based on DNA sequence data of four chloroplast markers and one nuclear marker. There is little congruence between our molecular results and previous morphology-based infrageneric classifications. However, some similarities can be found, including Fyson's sect. Leucantherae and Zhang's sect. Apoda. Further phylogenetic studies, particularly focusing on less well sampled regions such as the Neotropics, will help provide a more global overview of the relationships in Eriocaulon and may enable suggesting the first global infrageneric classification.

Syngonanthus androgynus, a Striking New Species from South America, its Phylogenetic Placement and Implications for Evolution of Bisexuality in Eriocaulaceae.

In the present study, we describe and illustrate a remarkable new species of Syngonanthus from South America (Bolivia, Brazil and Peru). This new species is quickly distinguished from all species in the genus by trimerous and bisexual flowers, a unique set of characteristics in Syngonanthus. Complementary to this study, sequences of 33 species were downloaded from GenBank and four species had sequences newly generated for this study. Molecular phylogenetic analyses based on nuclear ribosomal ITS and the plastid regions psbA-trnH and trnL-F were performed to determine its systematic position. The results have shown S. androgynus closely related to a well-supported clade that has been treated as Syngonanthus sect. Carphocephalus. Floral traits associated with this new plant also were surveyed. Character reconstruction suggests that the bisexual flowers originated independently more than once in the genus. However, trimerous flowers appear to be an ancestral condition of the whole genus.

Soil factors effects on life history attributes of Leiothrix spiralis and Leiothrix vivipara (Eriocaulaceae) on rupestrian grasslands in Southeastern Brazil / Efeitos de fatores do solo nos atributos de história de vida de Leiothrix spiralis e Leiothrix vivipara (Eriocaulaceae) nos campos rupestres no Sudeste do Brasil.

In this study, we hypothesized that the life history traits of Leiothrix spiralis and L. vivipara would be linked to soil factors of the rupestrian grasslands and that rosette size would be influenced by soil moisture. Soil analyses were performed from five populations of L. spiralis and four populations of L. vivipara. In each area, three replicates were employed in 19 areas of occurrence of Leiothrix species, and we quantified the life history attributes. The microhabitats of these species show low favorability regarding to soil factors. During the dry season, their rosettes decreased in diameter due the loss of its most outlying leaves. The absence of seedlings indicated the low fecundity of both species. However, both species showed rapid population growth by pseudovivipary. Both L. spiralis and L. vivipara exhibit a kind of parental care that was quantified by the presence of connections between parental-rosettes and ramets. The findings of the present study show that the life history traits are linked to soil factors.

Neste estudo, testamos a hipótese de que os traços da história de vida de Leiothrix spiralis e L.vivipara estariam ligados a fatores do solo dos campos rupestres, e que o tamanho de roseta seria influenciado pela umidade do solo. As análises de solo foram realizadas a partir de cinco populações de L. spiralis e quatro populações de L. vivipara. Em cada área, três repetições foram empregadas em 19 áreas de ocorrência das espécies de Leiothrix, e quantificamos os atributos de história de vida. Os microhabitats destas espécies apresentam baixa “favorabilidade” em relação aos fatores de solo. Durante a estação seca, as rosetas diminuíram de diâmetro devido à perda de suas folhas mais periféricas. A ausência de plântulas indicou a baixa fecundidade de ambas as espécies. No entanto, ambas as espécies apresentaram crescimento rápido da população por pseudoviviparidade. Tanto L. spiralis quanto L. vivipara exibem um tipo de cuidado parental que foi quantificada pela presença de conexões entre rosetas parentais e rametes. Os resultados do presente estudo mostram que os traços da história de vida estão ligados aos fatores do solo.

Body size and clonality consequences for sexual reproduction in a perennial herb of Brazilian rupestrian grasslands.

Body size is one of the most important factors regarding herbaceous perennial plants life-histories, and several fitness components of these organisms are related to size. Clonal plants show distinct kinds of reproduction and can develop offspring by sexual or asexual ways. We aimed to understand how body size affects Comanthera nivea (Eriocaulaceae) sexual reproduction and to verify how clonal growth is related to flower head production in this species. We sampled 600 rosettes in rupestrian grasslands and performed linear regression analysis between body size and number of produced flower heads. We also compared the flower head production between isolated rosettes and rosettes within clones. Our results showed that body size was significantly related, but explained only a small part of flower head production. The flower head production was higher in rosettes within clones than in isolated ones. The clones presented a rosette or a small group of rosettes that concentrated the sexual reproduction. Clonality was positively associated with sexual reproduction. Clonality can represent an important way of allowing the persistence of plants by sexual reproduction in markedly seasonal stressful environments. The cases of clonality enhancing the sexual reproduction must be considered and put in focus on reproductive biology research.

Body size and clonality consequences for sexual reproduction in a perennial herb of Brazilian rupestrian grasslands / Consequências do tamanho de corpo e da clonalidade para a reprodução sexuada de uma herbácea perene doa campos rupestres brasileiros

Body size is one of the most important factors regarding herbaceous perennial plants life-histories, and several fitness components of these organisms are related to size. Clonal plants show distinct kinds of reproduction and can develop offspring by sexual or asexual ways. We aimed to understand how body size affects Comanthera nivea (Eriocaulaceae) sexual reproduction and to verify how clonal growth is related to flower head production in this species. We sampled 600 rosettes in rupestrian grasslands and performed linear regression analysis between body size and number of produced flower heads. We also compared the flower head production between isolated rosettes and rosettes within clones. Our results showed that body size was significantly related, but explained only a small part of flower head production. The flower head production was higher in rosettes within clones than in isolated ones. The clones presented a rosette or a small group of rosettes that concentrated the sexual reproduction. Clonality was positively associated with sexual reproduction. Clonality can represent an important way of allowing the persistence of plants by sexual reproduction in markedly seasonal stressful environments. The cases of clonality enhancing the sexual reproduction must be considered and put in focus on reproductive biology research.

O tamanho de corpo é um dos atributos de história de vida mais importantes para plantas herbáceas perenes e muitos componentes da aptidão desses organismos são relacionados ao tamanho. As plantas clonais apresentam diferentes tipos de reprodução e podem gerar prole por vias sexuadas ou assexuadas. Nosso objetivo foi compreender como o tamanho de corpo afeta a reprodução sexual em Comanthera nivea e verificar como o crescimento clonal relaciona-se à produção de capítulos dessa espécie. Nós amostramos 600 rosetas em campos rupestres e utilizamos regressões lineares para verificar a relação entre o tamanho de corpo e o número de capítulos produzidos pela planta. Nós também comparamos a produção de capítulos entre rosetas isoladas e rosetas pertencentes a clones. Nossos resultados mostram que o tamanho de corpo tem influência positiva significativa na produção de capítulos, mas explica apenas parte da variação nos dados. A produção de capítulos é maior em rosetas pertencentes a clones que em rosetas isoladas. Os clones geralmente apresentam uma roseta, ou um grupo de rosetas, que concentra a reprodução sexual. A clonalidade apresentou ligações significativas com a reprodução sexuada. Em ambientes sazonais a clonalidade pode representar uma importante forma de persistência das plantas já que pode permitir um melhor desempenho da reprodução sexuada em vista dos estresses ambientais. Os casos nos quais a clonalidade representa uma via de melhor desempenho para a reprodução sexuada devem ser considerados e colocados em foco na pesquisa em biologia reprodutiva.

Soil factors effects on life history attributes of Leiothrix spiralis and Leiothrix vivipara (Eriocaulaceae) on rupestrian grasslands in Southeastern Brazil.

In this study, we hypothesized that the life history traits of Leiothrix spiralis and L. vivipara would be linked to soil factors of the rupestrian grasslands and that rosette size would be influenced by soil moisture. Soil analyses were performed from five populations of L. spiralis and four populations of L. vivipara. In each area, three replicates were employed in 19 areas of occurrence of Leiothrix species, and we quantified the life history attributes. The microhabitats of these species show low favorability regarding to soil factors. During the dry season, their rosettes decreased in diameter due the loss of its most outlying leaves. The absence of seedlings indicated the low fecundity of both species. However, both species showed rapid population growth by pseudovivipary. Both L. spiralis and L. vivipara exhibit a kind of parental care that was quantified by the presence of connections between parental-rosettes and ramets. The findings of the present study show that the life history traits are linked to soil factors.

Inflorescences in Eriocaulaceae: taxonomic relevance and practical implications.

BACKGROUND AND AIMS: Inflorescences are thought to be of enormous taxonomic relevance; however, at the same time they are regarded as being notoriously difficult. This is partly due to the conflicting needs of floristics and evolutionary botany, but partly also due to the complicated and confusing terminology introduced by W. Troll and his school. METHODS: The branching patterns of representatives of the genera Eriocaulon, Syngonanthus and Paepalanthus have been studied in the field and from preserved material by scanning electron microscopy. Branching patterns and formation sequences have been analysed and documented in longitudinal schemes and diagrams. Repetitive units of different levels are detected and related to the body plans of other species of the family. KEY RESULTS: The repetition of very few different branching patterns on different levels of complexity may lead to highly complex inflorescences. However, terms are needed only for patterns; levels may be numbered consecutively. While complex inflorescences are often described as additions or aggregations of units, there is some evidence that complex inflorescences are often the result of fractionation of inflorescence meristems. CONCLUSIONS: Precise descriptions of inflorescences useful for diagnostics and phylogenetics can be much simpler than they often are today. If complex inflorescences are the result of meristem fractionation, intermediate morphotypes cannot be expected. On the other hand, such intermediate morphotypes should occur if a complex inflorescence is formed following an aggregation pathway. Unless the repetitive patterns shown here are not correlated to complementary gene activities the inflorescences are not fully understood.

Chemistry in Eriocaulaceae.

Eriocaulaceae is a pantropical family that comprises about 1100 species distributed in 11 genera. The infrafamilial relationships are still unsatisfactorily resolved, because of the tiny flowers and generalized morphology, which makes the taxonomy very difficult. Flavonoid and naphthopyranone profiles have proved to be important in order to contribute to the alignment of genera into the family. We here present a survey of the chemical data of Eriocaulaceae with a discussion about their contribution to the taxonomy of Eriocaulaceae.

Floral anatomy of Paepalanthoideae (Eriocaulaceae, Poales) and their Nectariferous structures.

BACKGROUND AND AIMS: Eriocaulaceae (Poales) is currently divided in two subfamilies: Eriocauloideae, which comprises two genera and Paepalanthoideae, with nine genera. The floral anatomy of Actinocephalus polyanthus, Leiothrix fluitans, Paepalanthus chlorocephalus, P. flaccidus and Rondonanthus roraimae was studied here. The flowers of these species of Paepalanthoideae are unisexual, and form capitulum-type inflorescences. Staminate and pistillate flowers are randomly distributed in the capitulum and develop centripetally. This work aims to establish a floral nomenclature for the Eriocaulaceae to provide more information about the taxonomy and phylogeny of the family. METHODS: Light microscopy, scanning electron microscopy and chemical tests were used to investigate the floral structures. KEY RESULTS: Staminate and pistillate flowers are trimerous (except in P. flaccidus, which presents dimerous flowers), and the perianth of all species is differentiated into sepals and petals. Staminate flowers present an androecium with scale-like staminodes (not in R. roraimae) and fertile stamens, and nectariferous pistillodes. Pistillate flowers present scale-like staminodes (except for R. roraimae, which presents elongated and vascularized staminodes), and a gynoecium with a hollow style, ramified in stigmatic and nectariferous portions. CONCLUSIONS: The scale-like staminodes present in the species of Paepalanthoideae indicate a probable reduction of the outer whorl of stamens present in species of Eriocauloideae. Among the Paepalanthoideae genera, Rondonanthus, which is probably basal, shows vascularized staminodes in their pistillate flowers. The occurrence of nectariferous pistillodes in staminate flowers and that of nectariferous portions of the style in pistillate flowers of Paepalanthoideae are emphasized as nectariferous structures in Eriocaulaceae.

Seasonal timing of pseudoviviparous reproduction of Leiothrix (Eriocaulaceae) rupestrian species in South-eastern Brazil.

BACKGROUND AND AIMS: Pseudovivipary is an asexual reproductive strategy. Leiothrix spiralis and L. vivipara (Eriocaulaceae) are pseudoviviparous and occur in rupestrian grasslands, a habitat that has a predominance of sandy and shallow soil, with low water retention. This study aims to investigate the seasonal variation effect of moisture availability on L. spiralis and L. vivipara pseudoviviparous reproduction, and to compare their life history attributes, on rupestrian grasslands in Southeastern Brazil. METHODS: A field study was conducted, including observations concerning pseudoviviparous reproduction and measurement of demographic variables in both L. spiralis and L. vivipara. Soil moisture measurements were also performed to study its effect on the pseudoviviparous reproduction of L. spiralis and L. vivipara. KEY RESULTS: Flower head and plantlet production in L. spiralis were highly correlated with soil moisture. All scapes split off in the drier period, indicating that this is a splitter ramet species. Plantlet mortality was positively correlated with scapes splitting off. The L. vivipara phenophases were not synchronized to the variation in soil moisture, since flower heads and plantlets were produced throughout the year. Moreover, the splitting off of scapes was not observed. In addition, plantlets were formed early, as soon as the flower heads appeared, and remained suspended. Therefore, this species was called 'canopy forming'. CONCLUSIONS: Seasonal timing of pseudoviviparous reproduction can be a vital component of the successful establishment of plantlets in L. spiralis, considering that in this species the plantlets are formed only after the flower head touches the ground. In contrast, in L. vivipara, the plantlets are formed early, without touching the ground. Moreover, L. spiralis is a splitter ramet species, while L. vivipara is a canopy-forming species. The pseudoviviparous canopy-forming strategy appears to be more advantageous than the splitter ramet strategy, because even under similar soil moisture conditions, the survival of L. vivipara plantlets was greater than that of L. spiralis.